Your search resulted in 16 documents.
Water-based water repellents for treatment of wood
1987 - IRG/WP 3446
The water uptake by wood can be reduced by treatment with a water repellent. The water repellents most commonly used are solvent based. In the present work a new type of water repellent that is water-based has been investigated. Two different treatments have shown an effect of the same order as a commercial solvent based product. The cellular distribution of the water repellents has been investiga...
I G Svensson, G Hägglund, I Johansson, W B Banks
Experiences with penetration of copper-based wood preservatives
2001 - IRG/WP 01-20233
In the Nordic countries there is a long tradition of result type based specifications for preservative-treated wood. A common Nordic standard for treated pine (Pinus sylvestris) wood was published in 1976. After a revision in 1989 this standard, then named INSTA 140, defined four classes of treated wood: M, A, AB and B. Treaters producing according to this standard had to be affiliated to a qualit...
J Jermer, F G Evans, I Johansson
Studies on the permeability of Norway spruce (Picea abies)
1987 - IRG/WP 2295
It is well known that the bordered pits play a dominating role for liquid transport in softwoods. The mechanism behind pit aspiration during drying or heartwood formation seems to be well understood. The reason why the fixation of the membrane (torus) to the pit opening remains almost irreversible is, however, still unclear. A technique has been developed combining so-called "solvent exchange dryi...
I Johansson, K Nordman-Edberg
Quality assured wooden sidings - Criteria, performance evaluations and current status
2000 - IRG/WP 00-20216
Quality assured wooden sidings were brought to the Swedish market in 1998. The system was worked out during a six year period in a close cooperation between the sawmill industry and several research institutes. Centuries of use have given a wealth of experience of spruce boards as a siding material, showing that it works well in most cases but also that its longevity is highly variable, depending ...
F Englund, I Johansson, J Ekstedt, R Nussbaum
Tilting and vacuum treatment - two methods to obtain a non-dripping freshly treated timber
1989 - IRG/WP 3535
Modern impregnation plants are designed to prevent spread of impregnation solutions from the plant through leakage, etc. It is also important that freshly treated timber does not spread solutions through dripping on the storage area. To prevent this, the impregnation procedure is terminated with a vacuum period. In many plants in Sweden this period is minimized or even excluded to gain time. Inste...
I Johansson, M-L Edlund
Modelling of onset of mould growth for wood exposed to varying climate conditions
2009 - IRG/WP 09-20414
A performance-based service life design format based on climatic exposure on one hand and “resistance” of wood against mould growth on the other hand, is presented in this paper. A limit state for onset of mould growth is defined as the occurrence of traces of mould observed by microscopy. A dose-response model is proposed by which onset of mould growth can be predicted for an arbitrary climat...
S Thelandersson, T Isaksson, A Ekstrand-Tobin, P Johansson
Mould growth on wood-based materials – a comparative study
2010 - IRG/WP 10-20455
Ten different wood-based materials - preservative-treated wood, fire retardant-treated wood, modified wood, WPCs and untreated references of pine sapwood and spruce - were tested for mould growth according to SP method 2899 during 42 days at 90% RH and 22°C.
Even though the results must be interpreted carefully, they indicate significant differences in mould resistance between the materials tes...
P Johansson, J Jermer
Field trials of wood preservatives in UC3 retention. Part 1. Durability results after 13 years in and above ground
2010 - IRG/WP 10-30548
In 1996 an extensive field trial program was set up in order to obtain more data on wood treated with chromium and arsenic free preservatives in Use Class 3 retention. Apart from durability in and above ground, other features were also assessed, e.g. discoloration by staining fungi, depletion of active ingredients, weathering and corrosion of fasteners in con¬tact with the treated wood. Wood spec...
M Westin, J Jermer, M-L Edlund, P Larsson Brelid, I Johansson
Re-use of casting timber
2011 - IRG/WP 11-50283
Re-use of casting timber could be a way of saving timber resources, particularly in countries where most timber for construction purposes has to be imported. The objective of the present study was to investigate residual concrete on casting timber re-used five times. Moulds were made of sections of Norway spruce, untreated and treated with a casting oil and a wax formulation applied by a vacuum-pr...
I Johansson, S Breyne, H Egnell, J Jermer
Mould growth on wood-based materials – a simulated in-service study
2012 - IRG/WP 12-20503
Ten different wood-based materials including preservative-treated wood, fire retardant-treated wood, modified wood, WPCs and untreated references of pine sapwood and spruce were placed in three different environments (an attic and two crawl spaces) for a period of 26 months. Mould growth was analysed at five to seven month intervals in an effort to map the growth development. The relative humidit...
G Bok, P Johansson, J Jermer
The effect on moisture content of water trapped in wood joints
2012 - IRG/WP 12-40613
To predict the service life of a structure, a model where the exposure of a structure is compared to its resistance can be used. Which exposure and resistance parameters that are relevant depend on which materials the structure consist of. This approach, with an exposure and a resistance parameter, is similar to the one used in structural engineering where a load (exposure) is compared to the bear...
M Fredriksson, L Wadsö, P Johansson
The influence of microclimate on the moisture conditions in a Norway spruce (Picea abies (L.) Karst.) joint exposed to artificial rain
2013 - IRG/WP 13-20505
Wood structures outdoors are susceptible to decay if they are exposed to high moisture contents during long periods of time. Structures with joints that act as water traps are especially exposed since high moisture contents are reached in such positions. This paper presents a part of a laboratory study that concerns the relationship between the microclimate and the material climate, i.e. the moist...
M Fredriksson, L Wadsö, P Johansson
The activity of a wood-decaying fungus during drying and rewetting cycles measured by isothermal calorimetry
2013 - IRG/WP 13-20526
Wood decaying fungi are an essential part of any ecosystems as they are the main decomposers of cellulose and lignin-containing materials. But as wood is a common building material the risk for decay fungi growth and subsequent degradation of our construction material is a concern. There are important physiological aspects of the growth and activity of decay fungi that are unknown today, and witho...
S Johansson, L Wadsö, A Pilgård, G Alfredsen
Method for determining the critical moisture level for mould growth on building materials
2013 - IRG/WP 13-20530
The natural conditions of relative humidity (RH) and temperature (T) in different parts of a building is rarely constant over time. Instead, RH and T often vary cyclically and may pose a risk of mould growth as these conditions are the two key environmental parameters that controls mould growth. Consideration to both humidity and temperature conditions and the susceptibility to mould in a material...
A Ekstrand-Tobin, P Johansson, G Bok
CT scanning of decay in creosoted poles for overhead lines
2013 - IRG/WP 13-30634
Creosote-treated poles have been examined by means of CT scanning in order to investigate the nature of soft spots that have been found more frequently during the last five years in Sweden. CT scanning provides a very good picture of the interior of the poles and decay can easily be detected. It was concluded that the soft spots in most cases were caused by decay which in turn had to do with extre...
C-J Johansson, A Clang, I Johansson, G Berggren
Critical moisture levels and mould resistance of five different wood treatments
2013 - IRG/WP 13-30632
Mould resistance of five different treatments were tested using two methods, a recently
developed method for the determination of critical moisture levels of building materials (RHcrit),
and ASTM D3273-94. The critical moisture level method exposed samples at 22 °C and 98, 92,
86 and 82% relative humidity (RH) for 12 weeks. ASTM D3273-94 was performed at 29 °C and
about 95% RH.
Treatments c...
G Bok, P Johansson, A Ekstrand Tobin, S Bardage